Source: pinterest.com

8. Cassandra Cain (Batgirl/Black Bat)

Cassandra Cain is hands down the most underrated Batman supporting character of all time. She NEVER gets the credit she deserves.

Cassie was born to David Cain and Lady Shiva, which was about as badass a pedigree as one could get. Like, you couldn't be a better killer if your parents were a ninja and a handgun. But after being raised as an assassin and taking her first life, Cassandra realized she never wanted to do it again. So she ran away.

Unfortunately, she had literally been designed as a weapon, with all of her skill being devoted to killing, leaving her mostly unable to talk or read. And, as it turns out, there aren't a lot of opportunities for a teenage girl who's mute, illiterate, and really good at murder. She sought out Oracle, and eventually earned a role as the new Batgirl, a badass crime fighting machine unlike any other.

What made Cassandra unique was that while the other batboys and girls decided not to kill based on the abstract concept that it was bad, Cassandra dealt with it as a practical reality and decided she hated it. What a badass.